1. Field of the Invention
The invention relates to an organic light emitting diode (OLED) pixel array. More particularly, the invention relates to an OLED pixel array having transmittance regions.
2. Description of Related Art
An OLED display is characterized by self-luminance, wide view angle, fast response speed, low operation voltage, low temperature operation, high photo-voltaic efficiency, and so on. Therefore, the OLED display is likely to become a mainstream of the next generation display. Among various OLED displays, a transparent OLED display attracts most attention. The transparent OLED display can be placed in front of another display, and therefore a user is able to observe images (i.e., external images) displayed by another display through the transparent OLED display.
Generally, in a conventional transparent OLED display, a transmittance region is located between every two sub-pixels. Patterns are formed by the transmittance regions that have small area and are arranged in line with the arrangement of the sub-pixels, and thus the spatial frequency of the transmittance regions is excessively high. As a result, the arrangement of the transmittance regions results in unfavorable imaging quality (e.g., image definition) of the external images observed through the transparent OLED display. Based on the above, how to develop a transparent OLED display to improve the imaging quality of the external images observed through the transparent OLED display is one of the issues to be resolved by researchers.